The number of hydronium ions is equal to the number of hydroxide ions in what kind of solution?

In a neutral solution, the number of hydronium ions (H₃O⁺) is equal to the number of hydroxide ions (OH⁻). This balance occurs at a pH of 7, which is typical for pure water at 25°C. In such solutions, the concentration of both ions is 1 × 10⁻⁷ moles per liter, maintaining equilibrium.